Stone tools now 3.3 million years old

15 Apr 2015

Sonia Harmand presented a talk at the Paleoanthropology Society meeting this week describing her team’s discovery of stone tools in a 3.3-million-year-old context at Lomekwi, on the west side of Lake Turkana. Michael Balter reported on the talk in a story in Science: “World’s oldest stone tools discovered in Kenya”:

In 2011, Harmand’s team was seeking the site where a controversial human relative called Kenyanthropus platyops had been discovered in 1998. They took a wrong turn and stumbled upon another part of the area, called Lomekwi, near where Kenyanthropus had been found. The researchers spotted what Harmand called unmistakable stone tools on the surface of the sandy landscape and immediately launched a small excavation.

The story discusses the contents of the talk, that the tools have been found both from surface and excavation contexts. According to the article, the artifacts show quantitative differences from known Oldowan assemblages, all of which are at least 700,000 years more recent. These differences led Harmand and colleagues to name a new tradition, which they are calling the “Lomekwian”.

I can’t really comment more informatively about this until the work is published so that I can evaluate it. The obvious implication is that stone tools were invented and used by multiple lineages of early hominins. Just as there were different styles of body shape and bipedal mechanics among early hominins, there were likely different styles of technical traditions. A few of these were stone, but almost certainly there were perishable tool traditions among most populations of early hominins. Just taking what we know from living chimpanzee populations, with different traditions of tool use, complex tool sets made from perishable materials, and occasional use of durable objects made from stone. All hominins added initially was the deliberate flaking of stone to make objects recognizable in the archaeological record.

That is to say, humans have elaborated upon a technical ability that is latent among all the apes. This technical ability rests upon social learning skills that are necessary in chimpanzee societies, and early hominin societies inherited those skills from the common ancestors of humans and chimpanzees. After millions of years of exploring this technical space, some experiments led to the manufacture of stone flakes and choppers. Possibly one or more experiments led to the manufacture of bone points or piercers, as evidenced at Swartkrans and Kromdraai, and often attributed to robust australopithecines.

Such traditions may or may not have been shared across different hominin populations. In chimpanzees, technical traditions are not widely shared, yet we know that they may last locally for at least a few thousand years. If a chimpanzee-like model applied across the Pliocene, traditions that lasted a few thousand years across local areas would occasionally be visible to archaeologists, if they were looking for them.

John Hawks is the Vilas-Borghesi Distinguished Achievement Professor of Anthropology at the University of Wisconsin—Madison. I work on the fossil and genetic record of human evolution (About me).

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